The present invention relates to a method and apparatus for analyzing a plurality of test items in liquid samples, and more particularly to a method and apparatus suitable for carrying out analysis of a plurality of test items on one reaction vessel train.
As known apparatus for carrying out the analysis for a plurality of test items by an automatic analyzer, a multi-item analyzer which has a plurality of reaction lines in which respective reactions for each test item proceed is disclosed in JP-B-57-21663, and a single-line multi-item analyzer which has only a single reaction line in which reactions for a plurality of test items proceed is disclosed in JP-B-55-21303. The latter is suitable for simplification of construction and it has been widely used.
However, in the prior art single-line multi-item analyzer, the reaction line is composed of a reaction vessel train, and a sample supply device, a reagent supply device and a reaction vessel washing device are fixedly arranged around the reaction line so that each reaction vessel stopped at a reaction vessel washing position is cleaned. As a result, a maximum time period for which the sample may stay on the reaction line is one cycle time of the reaction vessels.
On the other hand, where an extremely small quantity of component in vivo is to be analyzed by utilizing an antigen/antibody reaction, a long reaction time is frequently required. U.S. Pat. No. 4,837,159 discloses an immunological analyzer which separates a bound (B) antigen or antibody, and a free component (F) by cleaning. In the U.S. Patent, reaction containers are arranged on a turntable which forms a circular reaction line and enzyme immuno-assay is carried out on the single reaction line.
In the apparatus of the U.S. Patent, when a first group of samples is to be analyzed, time periods from the sampling to the washing the same for all samples supplied to the reaction line. After the first group of samples has been analyzed, an operating condition of the analyzer is modified for a group of samples to be analyzed next. Because of the modification of the operating condition of the analyzer, the time period from the sampling to the washing is set differently from that under the previous condition. However, the time periods from the sampling to the washing for those samples which are to be processed on the same reaction line are equal to each other.
In the U.S. Pat. No. 4,837,159, the analyzer is first used as a single-line single-item analyzer, and then used as the same analyzer for the next different items. Accordingly, it is very inconvenient when a plurality of test items are to be analyzed for each of many samples.